KR20040020636A - Single panel type color display device - Google Patents

Abstract

PURPOSE: One panel type color image display is provided to realize a wide range of color by utilizing a color separation device made of at least of four reflective type dichroic filters. CONSTITUTION: One panel type color image display includes a light source(100), a color separation device(220) and a light valve. The color separation device(220) is made of at least four reflective type dichroic filters so as to divide the light beam emitted from the light source(100) into a plurality of lights in response to wavelengths. And, the light valve generate a color image by controlling the light which is emitted from the light source(100) and is illuminated with being divided into a plurality of colors by the color separation device(220) in response to the image signal.

Description

Single-panel color image display device {Single panel type color display device}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type color image display device, and more particularly, to a single plate color image display device capable of obtaining a wide color range and / or high light efficiency.

Projection-type color image display devices use light valves such as liquid crystal displays (LCDs) or digital micro displays (DMDs) to form images by controlling the light emitted from a high-output lamp light source in units of pixels. In order to provide a large screen by enlarging and projecting the light using a projection optical system, it is divided into three plates and a single plate according to the number of light valves.

A typical single plate color image display device separates white light emitted from a lamp type light source into three colors R, G, and B using a color wheel, and sequentially sends each color to one light valve. The light valve is operated in accordance with this color sequence to form an image.

The conventional single-plate color image display device has a simpler optical structure and a smaller overall volume than the three-plate type in which the image of each color is represented by three light valves using an optical separation / combination system. There is a problem that the light efficiency drops to 1/3. In view of this, conventionally, a single plate type color image display device having a color light separator composed of three dichroic filters and exhibiting the same light efficiency as a three plate type has been proposed.

1 and 2, a conventional single-plate type color image display device having a dichroic filter type color light separator includes a lamp type light source 1 that emits white light and three dichroic filters disposed to be inclined with each other. 4R) (4G) 4B, micro lens array 10, and liquid crystal display element 20 are comprised.

The lamp type light source 1 emits light in the form of divergent light. The light emitted from the lamp type light source 1 is converted into parallel light by the condenser lens 3.

The white light emitted from the light source 1 is separated into red light R, green light G, and blue light B by three dichroic filters 4R, 4G, and 4B. The dichroic filter 4R reflects the red light R of the white light incident from the illumination unit and transmits the remaining color light. The dichroic filter 4G reflects the green light G of the color light transmitted through the dichroic filter 4R and transmits the remaining color light, that is, the blue light B. The dichroic filter 4B reflects blue light (B).

The three dichroic filters 4R, 4G and 4B are inclined by θ to each other to form a fan shape. That is, the dichroic filter 4R is inclined with respect to the dichroic filter 4G, and the dichroic filter 4B is inclined by + θ. Here, + means counterclockwise and-means clockwise.

Accordingly, the chief ray of the red light R is incident to the microlens array 10 at an angle inclined by −θ and the chief ray of the blue light B with respect to the chief ray of the green light G.

In the microlens array 10, a plurality of cylindrical lenses forming the microlens element 10a are arranged in a horizontal direction. The micro lens array 10 stripes red light (R), green light (G), and blue light (B) incident on different slopes on the signal electrodes 21R, 21G, and 21B of the liquid crystal display device 20. It focuses to a stripe shape.

The liquid crystal display device 20 has a structure in which the liquid crystal layer 23 is sandwiched between two transparent glass substrates 24 and 25, and the transparent conductive film 22 and the signal electrode 21R are formed on both surfaces of the liquid crystal layer 23. 21G and 21B are formed in a matrix structure.

In the conventional single-plate color image display device configured as described above, R and G are separated into three primary colors by three dichroic filters 4R (4G) and 4B and focused on the signal electrodes of the liquid crystal display element 20. The B color bars are arranged at regular intervals in the horizontal direction due to the difference in incidence angles of the chief rays of red light (R), green light (G), and blue light (B), and R, G, and B image signal electrodes 21R (21G) ( 21B). The R, G, and B signal electrodes 21R, 21G, 21B are subpixels. The R, G, and B signal electrodes 21R, 21G, 21B are assembled into one image pixel. ).

As described above, three sub-pixels corresponding to the three primary colors of R, G, and B correspond to the unit micro lens 10a, and these three sub-pixels correspond to the screen 7 by the field lens 5 and the projection lens 6. When the image is formed in, three subpixels are set and viewed as one image pixel.

On the other hand, as can be seen in FIG. 5 to be described later, the color range that can be realized when using three dichroic filters 4R (4G) and 4B as a color light separator is much higher than the color range that the human eye can recognize. narrow. The color range represents a range of reproducible chromaticity, and a narrow color range means that the number of reproducible colors is small.

Therefore, as in the conventional single-plate color image display device, the three dichroic filters 4R (4G) 4B are difficult to obtain a sufficient color range.

In addition, in the conventional single-plate color image display device as described above, since three subpixels constitute one image pixel, the resolution of the liquid crystal display element is reduced to 1/3. Therefore, there is a problem that the physical resolution of the liquid crystal display element 20 must be increased by three times in order to achieve the same resolution as compared with the projection type single-panel image display device using the color wheel.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a single-plate color image display device capable of realizing a wider color gamut.

In addition, the present invention can realize a wider color gamut and achieve the same resolution as when using a color wheel by the scrolling action of a spiral lens, and is capable of obtaining high light efficiency such as a three-plate type color image display. The purpose is to provide a device.

1 shows a conventional single plate color image display device having a color light separator consisting of three dichroic filters;

2 is a view illustrating a light path of the microlens array and the liquid crystal display of FIG. 1;

3 is a view schematically showing the configuration of a single-plate color image display device according to a first embodiment of the present invention;

4 is a view schematically showing the configuration of a single-plate color image display device according to a second embodiment of the present invention;

5 is a color coordinate shown by comparing the color range that can be realized by the color light separator according to the present invention with the color range for the sensitivity of the human eye and the color range for the conventional color light separator consisting of three dichroic filters,

6 is a view schematically showing a structure of a spiral lens applied to a single-plate color image display device according to the present invention;

7 is a cross-sectional view showing an embodiment of a lens cell of the spiral lens of FIG. 6;

FIG. 8 illustrates that when the light emitted from the light source is incident on the spiral lens without passing through the first cylinder lens and when the light emitted from the light source is incident on the spiral lens in a state where the width of the light emitted from the light source is reduced by the first cylinder lens, FIG. Figure showing the difference in the width of the light beams.

<Description of Symbols for Main Parts of Drawings>

100 ... light source 105,107 ... first and second cylinder lenses

110 ... Spiral Lens 111.Lens Cell

120,220 Colorimetric separator 131,135 First and second fly's eye lenses

137 ... relay lens 140 ... light valve

A single plate color image display device according to the present invention for achieving the above object is a light source; A color light separator comprising four or more dichroic filters of a reflection type to separate light emitted from the light source according to a wavelength; And a light valve emitted from the light source and separated by the color light by the color light separator, and irradiated with light to form a color image by controlling a pixel unit according to an input image signal.

The color light separator may include four dichroic filters configured to reflect red light, green light, cyan light, and blue light, respectively.

In addition, the color light separator may be composed of five dichroic filters configured to reflect red light, yellow light, green light, cyan light, and blue light, respectively.

In this case, the color light separator is preferably such that the dichroic filter reflecting red light is positioned last.

Preferably, the present invention further includes a spiral lens formed in a spiral shape such that a lens cell array is helically formed so as to produce a linear motion effect of the lens array during rotation.

Preferably, the present invention further includes first and second fly's eye lenses for transmitting light through the spiral lens in a 1: 1 correspondence to the lens cells of the spiral lens between the spiral lens and the light valve. Do.

The present invention may further include a relay lens for focusing the light passing through the second fly's eye lens between the second fly's eye lens and the light valve on the light valve according to a color. Do.

The present invention may further include first and second cylinder lenses, respectively, before and after the spiral lens so that the width of the light beam incident on the spiral lens is adjusted.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the single-plate color image display device according to the present invention.

3 and 4 are diagrams schematically showing the configuration of the single plate type color image display apparatus according to the first and second preferred embodiments of the present invention.

Referring to the drawings, the single-plate color image display device according to the present invention includes a light source 100, color light separators 120 and 220 for separating light incident from the light source 100 into color light, and And a light valve 140 for controlling light in units of pixels according to the image signal to form an image.

The light source 100 may include a lamp type light source that emits white light.

The color light separators 120 and 220 are formed of four or more dichroic filters of a reflection type to separate the white light incident from the light source 100 according to the wavelength, and the dichroic filter reflecting the red light R is positioned last. It is preferred to be arranged to be.

FIG. 3 shows four dichroic filters 120B, 120C, 120G and 120R such that the color light separator 120 reflects blue light (B), cyan light (C), green light (G), and red light (R), respectively. That is, the first to fourth dichroic filters 120B, 120C, 120G, and 120R include white light incident from the light source 100 toward blue light (B), cyan light (C), green light (G), and the like. The example shown to separate with red light (R) is shown.

In this case, the first to fourth dichroic filters are preferably provided to reflect blue light (B), cyan light (C), green light (G), and red light (R), and transmit the remaining color light.

As described above, when white light is incident from the light source 100 to the color light separator 120 including four dichroic filters 120B, 120C, 120G, and 120R, for example, the first dichroic filter 120B is incident. The blue light B is reflected among the white light, and the remaining color light is transmitted. The second dichroic filter 120C reflects the cyan light C of the light transmitted through the first dichroic filter 120B and transmits the remaining color light. The third dichroic filter 120G reflects the green light G of the light transmitted through the second dichroic filter 120C and reflects the remaining color light, that is, the red light R. The fourth dichroic filter 120R reflects the red light R transmitted through the third dichroic filter 120G.

Here, the arrangement order of the first to fourth dichroic filters 120B, 120C, 120G, and 120R may be variously modified.

Meanwhile, the intervals between the first to fourth dichroic filters 120B, 120C, 120G, and 120R may be divided into blue light (B), cyan light (C), and green light (G) separated by the color light separator 120. It is preferable that the red light R is determined to enter the same lens cell of the first fly's eye lens 131 to be described later without being mixed with each other.

3 illustrates an example in which the first to fourth dichroic filters 120B, 120C, 120G, and 120R of the color light separator 120 are parallel to each other. The first to fourth dichroic filters 120B and 120C are illustrated in FIG. 120G and 120R may be disposed to be inclined with each other.

4 shows five dichroic filters 220B and 220C so that the color light separator 220 reflects blue light (B), cyan light (C), green light (G), yellow light (Y), and red light (R), respectively. (220G) (220Y) and (220R) to separate the white light incident from the light source 100 into blue light (B), cyan light (C), green light (G), yellow light (Y), and red light (R). Shows an example.

The five dichroic filters 220B, 220C, 220G, 220Y, and 220R have a color light separator 120 composed of four dichroic filters 120B, 120C, 120G, and 120R. Similarly to the case of the first embodiment, it is preferable that blue light (B), cyan light (C), green light (G), yellow light (Y), and red light (R) reflect each other and transmit the remaining color light. . At this time, it is preferable that the dichroic filter 220R reflecting the red light R be positioned last.

In this case, the interval between the five dichroic filters 220B, 220C, 220G, 220Y, and 220R is the same lens of the first fly's eye lens 131 which is described later by the color light separated by the color light separator 220. It is desirable that the cells be arranged so that they do not mix with each other.

4 shows an example in which the five dichroic filters 220B, 220C, 220G, 220Y, and 220R constituting the color light separator 220 are parallel to each other, and the five dichroic filters 220B, 220C, ( 220G) 220Y and 220R may be arranged to be inclined with each other.

5 is when the color light separator according to the present invention consists of five dichroic filters to separate white light into blue light (B), cyan light (C), green light (G), yellow light (Y), and red light (R). The color range that can be realized is shown in comparison with the color range for the sensitivity of the human eye and the color range for the conventional color light separator consisting of three dichroic filters 4R (4G) 4B.

As illustrated in FIGS. 3 and 4, when the number of dichroic filters constituting the color light separators 120 and 220 is increased in comparison with the related art, as shown in FIG. Therefore, according to the color light separators 120 and 220 according to the present invention, a wider color range can be realized. Here, the wider color range means that the number of reproducible colors increases.

In addition, since the color light separators 120 and 220 according to the present invention have a structure in which a dichroic filter reflecting the red light R is positioned at the end, as illustrated in FIGS. 3 and 4, the color range may be wider. have.

Here, the reason why the color range becomes wider when the dichroic filter reflecting the red light R is placed at the end is as follows.

Looking at the spectral characteristics of the lamp-type light source 100, the intensity of the green light (G) is the strongest, the blue light (B) also shows a considerable intensity, while the intensity of the red light (R) is relatively weak.

Therefore, when the dichroic filter reflecting the red light R is placed in front, for example, since a considerable amount of the green light G is reflected by the dichroic filter together with the red light R, the green light G is applied to the red light R. This will be mixed in considerable quantities.

Since the human eye has good sensitivity to green light (G), the mixing of red light (R) with green light (G) makes it difficult to achieve proper color, and the color gamut range that can be represented by the image display device. To narrow it down.

However, as in the color light separators 120 and 220 according to the present invention, when the dichroic filter is disposed such that the red light R is reflected at the end, other red light R may be different from the green light G or the blue light B. The mixing of color light can be prevented, and the color range is prevented from being narrowed by color mixing. Therefore, according to the single plate type color image display device according to the present invention, a sufficiently wide color range can be realized.

Accordingly, the single-plate color image display device according to the present invention has a wider range of colors that can be expressed and the number of colors that can be expressed, compared to a conventional single-plate color image display device using three dichroic filters as color light separators. Increases.

On the other hand, when the color scrolling technology is applied to the single-plate color image display device, it is possible to achieve the same light efficiency as the three-plate type, and the resolution generated in the conventional single-plate color image display device as shown in FIG. No degradation problem occurs.

Color scrolling separates white light into multiple color lights and simultaneously sends them to different positions on the light valve to form multiple color bars and moves them in a specific way at a constant speed, It is a technique for forming a color image by reaching all the color light rays.

Accordingly, the single-plate color image display device according to the present invention preferably further includes a spiral lens 110 for color scrolling. First and second fly-eye lenses 131 and 135 may be further provided on the optical path between the spiral lens 110 and the light valve 140. In addition, a relay lens 137 may be further provided between the second fly's eye lens 135 and the light valve 140.

As shown in FIG. 6, the spiral lens 110 has a disk structure in which the array of lens cells 111 is helically formed so as to produce a linear motion effect of the lens array during rotation. The lens cells 111 are formed at equal intervals, and the cross-sectional shapes of the lens cells 111 are preferably the same.

For example, the lens cell 111 of the spiral lens 110 may be a cylindrical lens cell having an arc cross section as shown in FIG. 7. Alternatively, the lens cell 111 of the spiral lens 110 may be formed of a diffractive optical element or a holographic optical element type.

Each lens cell 111 of the spiral lens 110 functions as a focusing lens for focusing light incident from the light source 100.

When the spiral lens 110 including the spiral lens cell array 111 is rotated by a motor, the rotational motion of the spiral lens cell array 111 produces a linear motion effect of the lens array to cause the scrolling action. do.

That is, since the array of lens cells 111 is formed in a spiral shape, when the spiral lens 110 is rotated at a constant speed, the light beam L passing through a predetermined position of the spiral lens 110 is viewed as a reference. For example, an effect may be obtained such that the cylindrical lens array continuously moves up or down at a constant speed. At this time, when the width of the light beam L passing through the spiral lens 110 is narrow, the light beam L may have the same effect as passing through the cylindrical lens array linearly moving.

Accordingly, when the spiral lens 110 is rotated at a constant speed, the color lights separated by the color light separators 120 and 220 are repeatedly scrolled in accordance with the rotation of the spiral lens 110. The colorbar is scrolled on 140.

In this case, when the spiral lens 110 is provided as described above, scrolling may be implemented by continuously rotating in one direction without changing the rotation direction of the spiral lens 110, thereby maintaining continuity and consistency of color scrolling. Since the color bar is scrolled by one spiral lens 110, it is advantageous to maintain a constant scrolling speed of the color bar.

Here, the number of spiral lens cells 111 or the rotation speed of the spiral lens 110 in the spiral lens 110 may be adjusted to synchronize with the operating frequency of the light valve 140.

For example, when the operating frequency of the light valve 140 is faster, the number of lens cells 111 is provided so that the rotational speed of the spiral lens 110 is constant while the scrolling speed is adjusted faster, or the lens cell 111 is provided. By maintaining the same number and increasing the rotation frequency of the spiral lens 110 it is possible to adjust the scrolling speed faster.

3 and 4 show that the single-plate type color image display device according to the present invention includes one spiral lens 110, and two spiral lenses 110 as necessary. It is possible. Even when two spiral lenses 110 are provided, color scrolling can be implemented by installing two spiral lenses 110 on the same drive shaft, thereby maintaining a constant scrolling speed of the color bars.

When the dichroic filters constituting the color light separators 120 and 220 are parallel to each other, as shown in FIGS. 3 and 4, the spiral lens 110 includes the light source 100 and the color light separators 120 and 220. ), And the light focused by the spiral lens 110 is separated by the color light separators 120 and 220, by the difference in the light path length for each color light due to the selective reflection in each dichroic filter, It is preferable that different color lights enter the first fly's eye lens 131 without being mixed with each other.

Here, the dichroic filters constituting the color light separators 120 and 220 may be disposed to be inclined with respect to each other, and the spiral lens 110 may be disposed between the color light separators 120 and 220 and the light valve.

Each of the first and second fly's eye lenses 131 and 135 correspond to each other in a one-to-one correspondence, and one-to-one correspondence with each lens cell 111 of the spiral lens 110.

The first fly's eye lens 131 is positioned on the focal plane of the spiral lens 110 so that the color lights separated by the color light separators 120 and 220 are not mixed with each other via the spiral lens 110. It is desirable to.

In this case, the optical path length by dichroic filters focused by each lens cell 111 of the spiral lens 110 functioning as a focusing lens and separated by the color light separators 120 and 220 and spaced apart from each other. The color lights having a difference in focus are focused at different positions of the lens cells of the first fly's eye lens 131.

The color light passing through the first fly's eye lens 131 is converted into a divergent light form and is combined with the second fly's eye lens 135 to be incident to each other, and is converted into a parallel light form by the second fly's eye lens 135.

The relay lens 137 allows the color lights of the parallel light form via the first and second fly's eye lenses 131 and 135 to be imaged at different positions on the light valve 140 to form color bars for each color light. 3 and 4, the relay lens 137 is illustrated as a single lens, and the relay lens 137 may be formed of two or more lens groups.

When the first and second fly's eye lenses 131 and 135 and the relay lens 137 are provided as described above, the light collected by the spiral lens 110 is the first and the second fly's eye lenses 131. It is transmitted 1: 1 by the 135, and is imaged by color light-colored color bars on the light valve 140 by the relay lens 137.

The light valve 140 controls the color lights irradiated in the form of a color bar according to an input image signal to form a color image.

Color-specific color bars, such as R, G, C, B color bars or R, Y, G, C, B color bars formed on the light valve 140 are scrolled according to the rotation of the spiral lens 110. Therefore, when the image information for each pixel of the light valve 60 is processed in synchronization with the movement of the color bars for each color light, a color image is formed. The color image formed by the light valve 140 is enlarged by the projection lens unit (not shown) and is formed on the screen (not shown).

Meanwhile, the single-plate color image display device according to the present invention includes the first and second cylinder lenses 105 (before and after the spiral lens 110 so that the width of the light beam incident on the spiral lens 110 can be adjusted). It is preferable to further comprise 107).

The first cylinder lens 105 reduces the width of the light beam emitted from the light source 100 to be incident on the spiral lens 110, the second cylinder lens 107, the light passing through the spiral lens 110 It serves to return to the original state.

8 illustrates that when the light emitted from the light source 100 is incident on the spiral lens 110 without passing through the first cylinder lens 105 and the light emitted from the light source 100 passes through the first cylinder lens 105. The width difference of the light beam when the spiral lens 110 is incident in the state where the width thereof is reduced by) is compared.

As shown in the left part of FIG. 8, the light beam L 'when the light emitted from the light source 100 does not pass through the first cylinder lens 105 and passes through the spiral lens 110 is relatively wide. At this time, due to the spiral shape of the lens cell of the spiral lens 110, the shape of the light beam L 'and the shape of the lens cell are greatly inconsistent, resulting in light loss.

However, as shown in the right part of FIG. 8, when the width of the light beam is reduced by using the first cylinder lens 105, since the light beam L passes through the spiral lens 110 in a narrow width region, the relative width is relatively low. As a result, the spiral shape of the lens cell of the spiral lens 110 and the shape of the light beam may be substantially matched, thereby reducing light loss.

That is, by adjusting the width of the beam using the pair of cylinder lenses 105 and 107 as described above, the optical loss can be reduced.

In the above, the single-plate color image display device according to the present invention has been described with reference to a specific optical configuration, but the present invention is not limited thereto, and the single-plate color image display device according to the present invention is within the technical scope of the claims. Various modifications and equivalent other embodiments are possible.

The single-plate type color image display device according to the present invention as described above is provided with a color light separator composed of four or more dichroic filters of the reflection type, so that a wide color range can be realized.

In addition, the single-plate type color image display device according to the present invention implements color scrolling using a spiral lens having a spiral lens cell array, and thus maintains the same resolution as when using a color wheel. High light efficiency can be achieved.

In addition, since the single-plate color image display device according to the present invention includes a spiral lens for color scrolling, the optical structure is simple, so that the volume is small, the manufacturing cost is low, and the continuity and consistency of color scrolling can be maintained. The scrolling speed of the bar can be kept constant.

Claims (9)

A light source; A color light separator comprising four or more dichroic filters of a reflection type to separate light emitted from the light source according to a wavelength; And a light valve configured to form a color image by controlling the light emitted from the light source and separated and irradiated for each color light by the color light separator on a pixel-by-pixel basis according to an input image signal. . The single-color color image display device of claim 1, wherein the color light separator comprises four dichroic filters adapted to reflect red light, green light, cyan light, and blue light, respectively. The single-plate color image display device of claim 1, wherein the color light separator comprises five dichroic filters configured to reflect red light, yellow light, green light, cyan light, and blue light, respectively. The single-plate color image display device according to any one of claims 1 to 3, wherein the color light separator is configured such that a dichroic filter reflecting red light is positioned last. According to any one of claims 1 to 3, wherein the lens cell array is formed spirally so that the effect of the linear movement of the lens array during rotation, the spiral lens further configured to perform a scrolling action; Single plate type color image display device. 6. The single plate color image display device according to claim 5, wherein the spiral lens is positioned between the light source and the color light separator. 6. The apparatus of claim 5, further comprising: first and second fly-eye lenses between the spiral lens and the light valve so that light passing through the spiral lens is transmitted in a 1: 1 correspondence with respect to the lens cell of the spiral lens. A single-plate color image display device, characterized in that. The method of claim 7, further comprising: a relay lens for focusing the light passing through the second fly's eye lens between the second fly's eye lens and the light valve according to the color on the light valve. Single plate type color image display apparatus. The single-plate type color image display apparatus of claim 5, further comprising first and second cylinder lenses, respectively, before and after the spiral lens so as to adjust a width of the light beam incident on the spiral lens.